How to Create a Bootable USB on macOS

TL;DR:

Create a bootable USB on macOS in four steps: 1) download the macOS installer (Monterey and later from Apple's site; Catalina and earlier from the App Store); 2) format a 16GB+ USB in Disk Utility as Mac OS Extended (Journaled) with GUID Partition Map; 3) run sudo /Applications/Install\ macOS\ Sequoia.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume in Terminal; 4) boot it — hold Power on Apple silicon or Option on Intel. If your Mac won't boot at all, recover data first with Wondershare Recoverit.

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Creating a bootable USB on macOS lets you install or reinstall macOS, run diagnostics, or recover an unbootable Mac — no internet or App Store access needed. This guide covers the requirements, getting the installer, the Terminal createinstallmedia command, and booting on both Apple silicon and Intel.

Part 1. What Do You Need to Create a Bootable Installer

To create a bootable macOS USB, gather these items first:

Part 2. How to Get macOS Installer Files

How you get the installer depends on the macOS version:

For older versions, the Mac App Store links below open the installer download:

1. You will be directed to Apple's website. Click "View in Mac App Store" and select the "Open App Store" option from the prompt.
2. In the Mac App Store, click the "Get" button to download the macOS Installer. Once the download completes, the installer is stored in the Applications folder as Install macOS X (X is the OS name).

Part 3. Use Terminal to Create the USB Installer

The reliable way is a two-stage process: format the USB in Disk Utility, then run createinstallmedia in Terminal. Follow the steps below.

3.1 Format the USB Drive in Disk Utility

1. Connect the USB drive to your Mac. Press Command + Space, type Disk Utility, and launch it.
2. If you are using High Sierra or later, click the "View" option on the top left side of the screen, and from the drop-down menu, choose Show All Devices.

   

3. In the sidebar, select the USB drive — the root drive, not a volume under it. Click "Erase", and in the prompt choose Mac OS Extended (Journaled) as the format and GUID Partition Map as the scheme, then click "Erase". You can rename the USB here; you'll use that name in Terminal.

   

4. Wait for Disk Utility to finish creating the partition, then click "Done".

   

3.2 Run createinstallmedia in Terminal

1. Open Terminal from Applications > Utilities (or press Command + Space and type Terminal).

   

2. Copy the createinstallmedia command below that matches your macOS version, replace "MyVolume" with your USB drive's name, and press Enter.

   

Note: Replace "MyVolume" with the exact name your USB drive shows in Finder. The space before --volume matters; copy the command exactly.

1. Type your admin password and press Enter. When Terminal asks "To continue we need to erase the volume at /Volumes/MyVolume", type Y and press Enter. Wait until the progress reaches 100%.
2. After the copying finishes and "Done" appears, close Terminal. To verify, run diskutil list — the USB should appear with the installer's name (e.g. "Install macOS Sequoia") as its volume label.

Tip: add --nointeraction to the command to skip the Y/password prompts during the erase confirmation, useful for scripts or repeated builds: sudo .../createinstallmedia --volume /Volumes/MyVolume --nointeraction.

Your bootable USB drive is ready, and you can use it to install macOS on any Mac.

Part 4. How to Boot the Mac Using the Created Bootable USB Drive

Before booting, check whether your Mac has an Apple Silicon chip or an Intel processor, then follow the matching instructions.

For Mac with The M1 Apple Silicon Chip

1. Plug in the bootable USB flash drive into the USB port on your Mac system.
2. Press and hold the Power button until the startup options screen showing bootable volumes appears.
3. Choose the bootable USB drive and click "Continue", then follow the on-screen instructions in the macOS installer window.

For Intel-Based Mac Systems

1. Plug in the bootable USB drive into the USB port of your Mac.
2. Press the Power button and hold the Option key until the screen displaying bootable volume options appears.
3. Choose the bootable USB installer drive and press Return.
4. Select "Install macOS or OS X" from the Utilities window and click "Continue".
5. Follow the on-screen instructions to complete the installation.

Note: On T2 Intel Macs and Apple silicon Macs, external booting must be allowed: open Startup Security Utility (in Recovery Mode) and set Startup Security to Allow booting from external or removable media. On Apple silicon you'll be asked to approve the external boot with the side button / Touch ID.

Part 5. Use Disk Utility to Create the USB Installer

If you'd rather prepare the USB visually, format it in Disk Utility first and finalize it with Terminal afterward — simply copying the installer to a drive does not make it bootable.

Note: Dragging the installer onto the USB is not enough — you must still run the createinstallmedia command in Terminal to make it bootable.

1. Press Command + Space, type "Disk Utility", and press Return to launch it.
2. Insert your USB drive (minimum 16GB recommended).
3. In Disk Utility, select the USB drive from the sidebar, click "Erase", and configure Name, Format (Mac OS Extended / Journaled), and Scheme (GUID Partition Map). Then click "Erase" to format the drive.
4. After formatting, run the matching createinstallmedia command from Part 3 in Terminal to finish.

Boot the Mac from the USB Installer: shut down, reboot while holding the Option key (or Power on Apple silicon), select the USB installer, and follow the on-screen instructions. On Intel Macs you can also enter macOS Recovery by holding Command + R at startup.

Part 6. How to Recover Data from an Unbootable Mac

If you can't or don't want to reinstall macOS on an unbootable Mac, use recovery software to retrieve your files first. Wondershare Recoverit can create a bootable media drive and pull data from a crashed Mac. You'll need a blank 16GB+ USB, another working Mac, and Recoverit installed on that working Mac.

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Steps to Recover the Lost Data

1. Download and install Recoverit on your working Mac, launch it, and choose "Recover from Crash Computer" under the last tab, then click Start.

   

2. Insert a blank USB (16GB or more). It will appear in the drop-down box; if you have several drives, click the arrow and select the blank one. Click Start — Recoverit formats the USB to make it bootable, so back up any files on it first.

   

3. Click Format and wait for the bootable media to be created.
4. Plug the bootable USB into the crashed Mac, power it on while holding the Option key, and select Wondershare Recoverit Bootable Media Drive on the screen.
5. Choose the files you want to copy, connect an external hard drive to the crashed Mac, select it as the destination, and click Start Copy.
6. Once the copy finishes, all your data is safe on the external drive.

Closing Words

Create a bootable USB on macOS with a 16GB+ drive: download the installer (Apple's site for Monterey+, App Store for older), format it as Mac OS Extended with GUID, run the createinstallmedia command (add --nointeraction to skip prompts), then boot it via the Power key (Apple silicon) or Option key (Intel) — allowing external boot in Startup Security Utility on T2/Apple silicon. If the Mac won't boot, recover your files first with Wondershare Recoverit.